Zero-turn radius lawnmower with suspension system

ABSTRACT

Some embodiments of the invention provide an independent suspension system coupled to a main-frame of ride-on equipment including a subframe coupled to the main frame with a pivot including a pivot axis. Some embodiments include a transaxle assembly supported on the subframe coupled to a drive wheel, and a power source supported on the main frame coupled to the transaxle assembly. A rider can control the transaxle assembly with a compensated control linkage assembly that can compensate for movement of the subframe. Some embodiments include driven pulleys, idler pulleys and backside idler pulleys supported by the subframe coupled to the power source not supported by the subframe. In some embodiments, the pivot axis resides between the power source and the transaxle assembly. In some embodiments, the drive wheel can be driven by an electric motor supported by the subframe and the power source can be a battery.

RELATED APPLICATIONS

This application claims priority under 35 U.S.C. §119 to U.S.Provisional Patent Application No. 61/677,288 filed on Jul. 30, 2012,and U.S. Provisional Patent Application No. 61/643,809 filed on May 7,2012, the entire contents of which are incorporated herein by reference.

BACKGROUND

Hydrostatic transaxles have become prevalent in the ZTR mower industry.Hydrostatic transaxles combine the hydraulic pump and one or morehydraulic wheel motors into a single unit, thereby simplifying andreducing the overall cost of the drive system of ZTR mowers and otherhydraulically-driven devices. The hydraulic pump of the hydraulictransaxle is mechanically driven by an internal combustion engine (orsimilar drive unit) via a belt-and-pulley system, and the hydraulic pumpin turn drives the hydraulic motor for each drive wheel. However, due tothe integration of the hydraulic pump and hydraulic wheel motors into asingle unit, suspension of the drive wheels on a ZTR mower utilizinghydrostatic transaxles presents several challenges. One of the foremostchallenges is the variation in belt angle between the drive pulleycoupled to the power take-off shaft of the internal combustion engine,and the driven pulley(s) of the hydraulic pump on the hydrostatictransaxle. If the belt angle between the drive and driven pulley(s) istoo great, the belt may run off of one or more the pulleys and renderthe drive system inoperable, or may wear at an unacceptable rate. Due tothese challenges, suspension of drive wheels driven by hydrostatictransaxles has been generally avoided.

SUMMARY

Some embodiments of the invention provide an independent suspensionassembly pivotally coupled to a main-frame of ride-on equipment. In someembodiments, the independent suspension assembly includes a main frame,a power source, such as an internal combustion engine, a seat foraccommodating at least one operator, and a subframe including a pivotand a pivot axis. Some embodiments include a first and second supporteach having a first end, and each coupled by at least one substantiallyhorizontal third support. In some embodiments, the pivot is coupled tothe first end of the first support and the first end of the secondsupport. In some embodiments, the pivot is configured and arranged toenable pivotal rotation of the subframe on the main frame around thepivot axis. In some further embodiments, the pivot axis residessubstantially between the at least one transaxle assembly coupled to thesubframe and the at least one external power source coupled to the mainframe.

In some embodiments, the independent suspension assembly includes atleast one motion absorbing suspension component including a first endcoupled to the main frame and a second end coupled to a second end ofthe first support or a second end of the second support or both. In someembodiments, the at least one motion absorbing suspension component is ashock absorber which can be a coil-spring type shock.

Some further embodiments can include at least one transaxle assemblysupported by the subframe and coupled to at least one external powersource. In some embodiments, the transaxle assembly can be configuredand arranged to be capable of being driven by the at least one externalpower source. In some embodiments, the transaxle assembly can includeone or more hydrostatic axles.

In some embodiments, the at least one transaxle assembly can include atleast one driven pulley positioned substantially within the subframe andcoupled to at least one component that is supported by the subframe. Insome embodiments, the driven pulley can be capable of being coupled tothe external power source by least one driven belt. In some furtherembodiments, the at least one transaxle assembly is configured andarranged to be capable of being driven by the at least one externalpower source during pivotal motion of the subframe about the main-frame.

In some alternative embodiments of the independent suspension assembly,the at least one external power source can be a current source such as abattery, and the at least one transaxle assembly can include at leastone electric motor capable of being driven be the current source. Someembodiments include an independent suspension assembly with at least oneexternal power source coupled to the at least one transaxle assembly viaat least one drive shaft capable of driving the at least one transaxleassembly.

Some embodiments of the independent suspension assembly include a firstbell crank pivotally coupled to a compensator arm, a first controllinkage and a second control linkage. In some embodiments, thecompensator arm is mounted to the subframe, and a second bell crankincluding a second axis is pivotally coupled to the subframe, the secondcontrol linkage, the first control linkage and the at least one drivecomponent. In some embodiments, the second bell crank is configured andarranged to at least partially actuate the at least one drive componentwhen the first bell crank rotated. Some further embodiments of theindependent suspension assembly include at least one control paddleassembly coupled to the main frame and the at least one compensatedcontrol linkage via the first control linkage. In some embodiments, theat least one control paddle is configured and arranged to move the firstbell crank.

In some embodiments of the invention, the subframe and the compensatedcontrol linkage are configured and arranged so that during a compressionof the at least one motion absorbing suspension component, when thedecrease of component length is two inches, the angle between the firstaxis of the subframe and the second axis of the second bell crank is nogreater than 1.32 degrees.

Some embodiments of the independent suspension assembly can also includea pulley and belt drive assembly including at least one belt idlerpulley positioned substantially within the subframe and coupled to atleast one component that is supported by the subframe. In someembodiments, the at least one belt idler pulley is positionedsubstantially in the same plane as the at least one driven pulley. Someembodiments include at least one backside idler pulley positionedsubstantially within the subframe and coupled to at least one componentthat is supported by the subframe. In some other embodiments, the atleast one backside idler pulley is positioned substantially in the sameplane as the at least one driven pulley and the at least one belt idlerpulley, as well as any other backside idler pulley positionedsubstantially within the subframe and is coupled to at least onecomponent that is supported by the subframe. Some embodiments include atleast one endless belt coupled with the at least one driven pulley, theat least one belt idler pulley and the at least one backside idlerpulley. In some other embodiments, the at least one endless belt isfurther coupled with at least one drive pulley positioned substantiallyoutside the subframe, and the drive pulley is configured and arranged sothat it does not pivot around the pivot axis. In some furtherembodiments of the independent suspension assembly, the at least onedrive pulley is coupled to a power take-off shaft.

Some alternative embodiments include an independent suspension assemblycomprising an auxiliary drive pulley coupled to the power take-offshaft. In some embodiments, the at least one drive pulley is configuredand arranged to rotate the at least one backside idler pulleys. In someother embodiments, the at least one drive pulley is configured andarranged to rotate the driven pulley. In some embodiments, at least aportion of the driven belt is located above the pivot axis.

In some embodiments, the independent suspension assembly includes asubframe and the compensated control linkage that is configured andarranged so that during compression of the at least one compressiblecomponent causing a decrease of component length of two inches, theangle between the first axis of the subframe and the second axis of thesecond bell crank is not greater than 1.32 degrees and the change ofbelt angle between the at least one backside idler pulleys and the drivepulley is not greater than 3 degrees.

Other embodiments of the independent suspension assembly furthercomprise a cutter assembly coupled to the auxiliary drive pulley by atleast one belt. Some other embodiments include a mower deck is coupledto and supported (directly or indirectly) by the main frame.

Some embodiments of the invention include an independent suspensionassembly pivotally coupled to a main-frame of ride-on equipment thatincludes at least one electric motor supported by the subframe. In someembodiments, the at least one electric motor is electrically coupled toat least one battery positioned external to the subframe and supportedby the main-frame. Some embodiments include a pivot axis locatedsubstantially between the at least one electric motor and the at leastone battery, and in some further embodiments, the electric motor iscapable of being powered by the at least one battery for driving atleast one drive member.

Some embodiments include an independent suspension assembly pivotallycoupled to a main-frame of ride-on equipment comprising a first supporthaving a first support first end and a second support having a secondsupport first end. In some embodiments, a first bushing is coupled tothe first support first end, and a second bushing is coupled to thesecond support first end. Some embodiments include a third supporthaving a third support first end affixed to a first support second end.In some embodiments, a third support second end is coupled to the secondsupport second end. Some embodiments of the independent suspensionassembly also include a pivot mounting the first support and the secondsupport to a substantially horizontal chassis support and including apivot axis.

Some embodiments include at least one electric motor supported by atleast one of the first support, the second support and the thirdsupport. In some other embodiments, the at least one electric motor iselectrically coupled to at least one battery supported by the mainframeand substantially unsupported by any of the first support and the secondsupport and the third support. Some other embodiments include at leastone electric motor that is configured and arranged to be powered by theat least one battery for driving at least one drive member and includinga pivot axis that is located substantially between the at least oneelectric motor and the at least one battery.

DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an isometric view of a ZTR mower in accordance withsome embodiments of the invention.

FIG. 2 illustrates a side sectional view of ZTR mower components inaccordance with some embodiments of the invention.

FIG. 3 illustrates a side sectional view of ZTR mower components inaccordance with some embodiments of the invention.

FIG. 4A shows a perspective view of ZTR mower components and suspensionsystem in accordance with some embodiments of the invention.

FIG. 4B shows a partial perspective view of ZTR mower components andsuspension system in accordance with some embodiments of the invention.

FIG. 5 shows a side sectional view of a suspension system in accordancewith another embodiment of the invention.

FIG. 6 shows a side sectional view of a suspension system in accordancewith another embodiment of the invention.

FIG. 7 illustrates a perspective view of a hydrostatic transaxle controlsystem in accordance with embodiments of the invention.

FIG. 8 shows a side sectional view of a hydrostatic transaxle controlsystem in accordance with one embodiment of the invention.

FIG. 9 shows a side sectional view of a hydrostatic transaxle controlsystem in accordance with another embodiment of the invention.

FIG. 10 a illustrates a perspective close-up view of the lower portionof the compensated control linkage assembly in accordance with anotherembodiment of the invention.

FIG. 10 b illustrates a perspective close-up view of the upper portionof the compensated control linkage assembly in accordance with anotherembodiment of the invention.

FIG. 11 illustrates a perspective view of a subframe and hydrostatictransaxles in accordance with some embodiments of the invention.

FIG. 12 illustrates a perspective view of a subframe and hydrostatictransaxles in accordance with some embodiments of the invention.

FIG. 13 illustrates a top sectional view of the hydrostatic transaxledrive system components in accordance with some embodiments of theinvention.

FIG. 14 a illustrates a close-up perspective view of a hydrostatictransaxle drive system in accordance with some embodiments of theinvention.

FIG. 14 b illustrates a close-up perspective view of a hydrostatictransaxle drive system in accordance with some embodiments of theinvention.

DETAILED DESCRIPTION

Before any embodiments of the invention are explained in detail, it isto be understood that the invention is not limited in its application tothe details of construction and the arrangement of components set forthin the following description or illustrated in the following drawings.The invention is capable of other embodiments and of being practiced orof being carried out in various ways. Also, it is to be understood thatthe phraseology and terminology used herein is for the purpose ofdescription and should not be regarded as limiting. The use of“including,” “comprising,” or “having” and variations thereof herein ismeant to encompass the items listed thereafter and equivalents thereofas well as additional items. Unless specified or limited otherwise, theterms “mounted,” “connected,” “supported,” and “coupled” and variationsthereof are used broadly and encompass both direct and indirectmountings, connections, supports, and couplings. Further, “connected”and “coupled” are not restricted to physical or mechanical connectionsor couplings.

The following discussion is presented to enable a person skilled in theart to make and use embodiments of the invention. Various modificationsto the illustrated embodiments will be readily apparent to those skilledin the art, and the generic principles herein can be applied to otherembodiments and applications without departing from embodiments of theinvention. Thus, embodiments of the invention are not intended to belimited to embodiments shown, but are to be accorded the widest scopeconsistent with the principles and features disclosed herein. Thefollowing detailed description is to be read with reference to thefigures, in which like elements in different figures have like referencenumerals. The figures, which are not necessarily to scale, depictselected embodiments and are not intended to limit the scope ofembodiments of the invention. Skilled artisans will recognize theexamples provided herein have many useful alternatives and fall withinthe scope of embodiments of the invention.

FIG. 1 illustrates an isometric view of a ZTR mower in accordance withsome embodiments of the invention. The ZTR mower 10 can include a mainframe 102, front caster wheels 106, and rear drive wheels 104 and a seat12. The ZTR mower 10 can also include a mower deck 31 including a frontcutter assembly 30 positioned between the front caster wheels 106 andrear wheels 104. Some embodiments can include front caster wheels 35mounted to the front cutter assembly 30 that aid in maintaining theheight of the front cutter assembly 30, thereby preventing damage fromrocks and other large debris. In some embodiments, the ZTR mower 10includes at least one power source. For example, in some embodiments,the mower 10 can include an engine, such as an internal combustionengine 108 shown behind the seat 12 in FIG. 1. In some embodiments, theengine 108 can be coupled to a power take-off shaft 109 (not shown). Insome embodiments, the power take-off shaft 109 is coupled to at leastone hydrostatic axles 114 (not shown) via an endless belt 132 (notshown). In some further embodiments, the ZTR mower 10 can also includeleft and right control paddles assemblies 134. In some furtherembodiments, the ZTE mower 10 can include alternative paddle assembly134 arrangements.

FIG. 2 shows a side sectional view of various ZTR mower components inaccordance with one embodiment of the invention. For ease ofunderstanding, many conventional components commonly present in ZTRmowers (e.g., control handles, seat, mower deck, etc.) have been omittedfrom FIG. 2. However, one of ordinary skill in the art will readilyunderstand that such conventional components may be included in theembodiments described herein. In some embodiments, the ZTR mower of FIG.2 comprises a main frame 102 supporting both rear drive wheels 104 andfront caster wheels 106. In some embodiments, the main frame 102 furthersupports an internal combustion engine 108, which operates to drive boththe drive wheels 104, other primary components, as well as one or moreauxiliary components attached to the ZTR mower, such as the cuttingblades of the front cutter assembly 30 (shown in FIG. 1). Someembodiments include the internal combustion engine 108 capable ofdriving the drive wheels 104 in addition to other components via one ormore drive pulleys, including a drive pulley 110 mounted to a powertake-off shaft 109 extending therefrom.

In some embodiments, the ZTR mower as illustrated in FIG. 2 furtherincludes a subframe 112 including a first axis 112 a pivotally mountedto main frame 102 about a pivot 115 including a pivot axis 116. In someembodiments, the subframe 112 may be mounted to main frame 102 using analternative technology that allows for substantially translationalmovement. In some embodiments, the subframe 112 supports thereon one ormore transaxle assemblies 114 a. For example, some embodiments includeone or more hydrostatic transaxles 114. In some embodiments, thetransaxles 114 contain both a hydraulic pump, a hydraulic valve (notshown), and a hydraulic motor (not shown) for powering the drive wheels104. Some embodiments can include one or more belt idler pulleys 118mounted on the subframe 112. In some further embodiments, the subframe112 further supports one or more backside idler pulleys 120 a, 120 b. Inother embodiments, idler pulley(s) 118 and backside idler pulleys 120 aand 120 b are attached to the subframe 112 via a spindle (not shown) toallow rotation of the pulley, and in some other embodiments, they can beattached via a plate 124, which may be integrally formed from thesubframe 112. In some embodiments, idler pulley(s) 118 and backsideidler pulleys 120 a, 120 b receive an endless belt 132 (not shown) thatis driven by drive pulley 110 on the power take-off shaft 109 ofinternal combustion engine 108. In some embodiments, the endless belt132 is also received by pulleys 122 a, 122 b coupled to the hydraulicpump of hydrostatic transaxle 114. In some embodiments of the invention,through this pulley-belt coupling, power from the internal combustionengine 108 is transferred to hydrostatic transaxle 114 via powertake-off shaft 109 to operate drive wheels 104. In some otherembodiments, alternative methods of driving hydrostatic transaxle 114,such as through a universal drive shaft can be used.

FIG. 3 shows another side sectional view of various ZTR mower componentsin accordance with one embodiment of the invention. As illustrated inthis view, the subframe 112 has travelled counterclockwise about pivotaxis 116 to illustrate a compressed state of the suspension system 103.As can be seen, each of the components mounted on subframe 112 rotateabout pivot axis 116, including idler pulley(s) 118, backside idlerpulleys 120, and at least one driven pulley 122 a, 122 b on hydrostatictransaxle 114. In some embodiments, power is transmitted from the drivepulley 110 via an endless belt 132. In some embodiments, the endlessbelt 132 can be an “A” section belt, although in other embodiments, a“V” section belt, a flat belt, or other type of belt can be used.

In some embodiments, as the suspension travels, the belt angle onlychanges between the back side idler pulleys 120 a, 120 b and the drivepulley 110 where the distance between these particular pulleys is thegreatest. Most notably, idler pulley(s) 118 and backside idler pulleys120 a, 120 b travel in the same plane (shown as pulley plane 400 inFIGS. 14 a and 14B) as the driven pulley 122 a, 122 b upon rotationabout pivot axis 116, which prevents belt misalignment between thesepulleys when subframe 112 travels through its suspension arc. Asdescribed earlier, if the idler pulleys 118, 120 a, 120 b were to travelor rotate about a different plane than driven pulleys 122 a, 122 b onhydrostatic transaxle 114 (i.e. not within pulley plane 400),significant belt misalignment may cause the belt 132 to “jump” or runoff of the pulley system and render the system inoperable. However, asshown in comparing FIG. 2 and FIG. 3, the only belt angle change betweenpulleys in the present embodiment would be between backside idlerpulleys 120 a, 120 b and drive pulley 110 mounted to the power take-offshaft 109. The risk of belt “jump” due to misalignment is greatlydiminished under this construction because there is a significantdistance between backside idler pulleys 120 a, 120 b and drive pulley110, thereby minimizing the belt angle change when subframe 112 travelsthrough its suspension arc. Furthermore, in general, backside idlerpulleys 120 a, 120 b have a higher tolerance for belt angle changesduring operation than other types of pulleys, and therefore the risk ofa belt 132 decoupling is greatly diminished.

FIGS. 4A and 4B show perspective views of various ZTR mower componentsin accordance with one embodiment of the invention. As discussedpreviously, the subframe 112 is pivotally coupled to main frame 102 at apivot 115 including a pivot axis 116. In some embodiments, the subframe112 comprises a first support 214 including a first end 214 a and asecond end 214 b, and a second support 216 having a first end 216 a anda second end 216 b. In some embodiments, the first support 214 andsecond support 216 are coupled by at least one substantiallyperpendicular and substantially horizontal third support 218. In someembodiments, the third support 218 is coupled to a first support secondend 214 b at a third support first end 218 a, and the third supportsecond end 218 b is coupled to a second support second end 216 b. Asdiscussed earlier, in some embodiments, the subframe 112 including afirst axis 112 a is pivotally mounted to the main frame 102 about apivot 115 including a pivot axis 116. In some embodiments, a pivot 115is coupled to the first end 214 a of the first support 214 and the firstend 216 a of the second support 216.

In some further embodiments, the subframe 112 is further coupled to amotion absorbing suspension component. In some embodiments, the motionabsorbing suspension component can include a compressible suspensioncomponent such as a coil spring-type suspension component 126. In someembodiments, a first end 126 a of the compressible suspension component126 is coupled to the main frame 102, and a second end 126 b of thecompressible suspension component is coupled to the subframe 112. Insome embodiments, the suspension component 126 is coupled to a secondend 214 b of the first support 214 or a second end 216 b of the secondsupport 216, or both.

In the perspective view of FIG. 4A, the subframe 112 is shown extendingcontinuously between both the right and left sides of main frame 102 tohold two hydrostatic transaxles 114, each of which can drive a separatedrive wheel 104 (not shown). As shown, the subframe 112 holds bothhydrostatic transaxles 114, each drive wheel 104 (not shown), and istranslated about the suspension arc of subframe 112 as the ZTR mowertravels across varying terrain. In some embodiments, the subframe 112need not extend continuously between the right and left sides of themain frame 102.

In some alternative embodiments of the invention, the subframe 112 caninclude two separate pivotal platforms (not shown), one for eachhydrostatic transaxle, to allow for independent suspension of each drivewheel (not shown). In some further embodiments of the invention thatinclude an independent suspension of each drive wheel, other variationsin the pulley arrangement can be included to account for movement of twoseparate pivotal platforms.

FIG. 5 shows another side sectional view of the suspension system 103according to one embodiment of the invention. In some embodiments, oneof the drive wheels 104 has been omitted from the figure for clarity. Asshown, in some embodiments, a compressible suspension component, such asa coil spring-type suspension component 126 is pivotally coupled to bothmain frame 102 (shown as 126 a) and subframe 112 (shown as 126 b). Thisarrangement allows for restricted rotation of subframe 112 about pivotaxis 116. In some other embodiments, the coil spring-type suspensioncomponent 126 can be replaced by any appropriate shock absorber. In someembodiments, the subframe 112 is pivotally coupled to a link 128, whichis in turn pivotally coupled to a bell crank 130. Some embodimentsinclude link 128 and bell crank 130 coupled to a mower deck (not shown)to allow corresponding movement of the mower deck in association withmovement of subframe 112. FIG. 6 shows a similar side sectional view asthat depicted in FIG. 5, but with coil spring-type suspension component126in a compressed position. Again, a comparison between FIG. 5 and FIG.6 clearly shows that all components mounted upon subframe 112 rotateabout pivot axis 116, including any desired idler pulleys (not shown)and the hydrostatic transaxle 114.

As discussed earlier, in some embodiments, the mower 10 can include afront cutter assembly 30 (FIG. 1 illustrates an isometric view of ZTRmower in accordance with some embodiments of the invention and shows afront cutter assembly 30 positioned between the front caster wheels 106and rear wheels 104). As shown in FIG. 5 and FIG. 6, some embodiments ofthe invention include an auxiliary pulley 111. In some embodiments, theauxiliary pulley 111 can be coupled to the engine 108 via a powertransfer assembly (e.g. a clutch assembly not shown) to enable therotational torque of the power take-off shaft 109 to drive the cutterassembly 30 by an endless belt (not shown). In some embodiments, a usercan control the coupling of the engine 108 to the cutter assembly 30through a conventional power transfer assembly, and in some furtherembodiments, the user can control the rotational speed of the auxiliarypulley 111 to control the cutter assembly 30. In some other embodiments,further auxiliary pulleys can be coupled to the power take-off shaft109. In other embodiments, one or more further auxiliary pulleys (notshown) can be coupled to one or more further conventional auxiliarycomponents (not shown).

In some embodiments, the mower 10 can include other features. Forexample, in some embodiments, a control linkage assembly 133 can be usedto control to power provided by an internal combustion engine 108. Forexample, FIG. 7 shows a perspective view of a control linkage assembly133 for operator control of hydrostatic transmission 114. In someembodiments, one or more hydrostatic transaxles 114 that combine ahydraulic pump (not shown) and hydraulic wheel motor (not shown) into asingle unit, are coupled to the engine 108 by a pulley and belt driveassembly 117. In some embodiments, an operator can deploy one or morecontrol paddles 134 to manipulate at least one hydrostatic transaxle 114to drive the drive wheels 104 (not shown). In some embodiments, anoperator can deploy one or more control paddles 134 to manipulate atleast one hydrostatic transaxle 114 to move in either a forward orreverse direction, or to remain neutral. In some embodiments, one ormore control paddles 134 coupled to the ZTR mower 10 can be coupled to ahydrostatic transaxle pump valve (not shown) to allow the control ofhydraulic fluid from one or more hydraulic pumps (not shown) within thehydrostatic axles 114.

As shown previously in FIGS. 4-6, in some embodiments, when the mower 10traverses a terrain, or when mower 10 is loaded and unloaded, the mainframe 102 can move with respect to the subframe 112. For example, whenan operator mounts the mower 10, or if additional weight or equipment isloaded onto the mower, the frame 102 can move with respect to thesubframe 112. Furthermore, during loading of the mower 10, in someembodiments, the coil spring-type suspension component 126, pivotallycoupled to both main frame 102 with the pivot 115, can compress, and thesubframe 112 can pivot about the pivot axis 116 on pivot 115. In someembodiments, because the subframe 112 can change the orientation ofhydrostatic transaxle 114 during a compressed condition, any directlinkage to hydrostatic transaxle 114 may cause an undesirable actuationof the hydrostatic transaxle pump valve (not shown) if one or morecontrol paddle(s) 134 were to be directly coupled to hydrostatictransaxle 114. Such an undesirable actuation of the hydrostatictransaxle pump valve may be unperceivable when the ZTR mower 10 ismoving, however it can become significantly more noticeable when the ZTRmower 10 is in the parked or neutral condition. In the parked or neutralcondition, compression of subframe 112 may occur due to operatormovement, or some other shifting of weight on the rear of the mower 10.If a direct linkage from control paddle(s) 134 to hydrostatic transaxle114 was used during such parked or neutral conditions, this weighting ofthe rear of the mower 10 may cause the linkage to open the hydrostatictransaxle pump valve enough to cause the machine to “lurch” until anunsuspended condition is again reached.

In some embodiments of the invention, a compensated control linkagesystem 133 can be used that comprises a first control linkage 136,including a first end 136 a and a second end 136 b, wherein the firstend 136 a is coupled to control paddle assembly 134, and the second end136 b is coupled to a first end 138 a of a bell crank 138. In someembodiments, the bell crank 138 is pivotally coupled to a component thatis coupled to the subframe 112 via a pivot axis 138 c. For example, asshown in FIG. 10 b, the bell crank 138 can be pivotally coupled to thecompensator arm 310 by pivot point 138 c. In some embodiments, a secondend 138 b of a bell crank 138 can be coupled to a first end 140 a of asecond control linkage 140. In some further embodiments, the second end140 b of a second control linkage 140 can be coupled to a second bellcrank (bell crank 142) used in operation of the hydrostatic transaxlepump valve (now shown). Most notably, in some embodiments, thecompensated control linkage system 133 straddles two regions of themower 10 that are supported around a pivoting component, pivot 115including pivot axis 116, the main frame 102 and the subframe 112. Someembodiments include a first control linkage 136 coupled via first end136 a to a paddle assembly 134 that is anchored to one region (the mainframe 102). Some embodiments also include the second end 136 b of firstcontrol linkage 136 coupled to a bell crank 138 that is directly coupledto compensator arm 310, which is anchored to the subframe 112.Therefore, in some embodiments, the bell crank 138 interposed betweenthe first control linkage 136 and second control linkage 140 asdescribed above can compensate for movement of subframe 112 and rotationabout pivot axis 116.

The embodiments as described can be further illustrated in FIG. 8 andFIG. 9 showing detailed side sectional views of the compensated controllinkage assembly 133 in accordance with one embodiment of the invention.As shown, FIG. 8 illustrates the mower 10 in an “uncompressed” condition(generally corresponding to the illustration of the suspension system103 as shown in FIG. 5, showing a suspension component 126 in agenerally extended, uncompressed condition). In some embodiments, theshock length of the embodiments shown in FIGS. 8 and 5 can be 10.5inches, and in this uncompressed condition, a 90 degree reference angleI is achieved between the couplings of bell crank 142 (shown as 142 aand 142 b) and a first axis 112 a on subframe 112. This positionsignifies a neutral condition of the mower when uncompressed.Conversely, FIG. 9 shows a “compressed” condition of the mower 10(generally corresponding to the illustration of the suspension system103 as shown in FIG. 6, showing a suspension component 126 in agenerally shortened, compressed condition). In some embodiments, theshock length of the embodiments shown in FIGS. 9 and 6 can be 8.5inches, and in this compressed condition, an 88.68 degree referenceangle I is achieved between operable couplings of bell crank 142 (shownas 142 a and 142 b, second axis 142 c) and the first axis 112 a onsubframe 112. In some embodiments, this change of angle I of 1.32degrees between the uncompressed and compressed conditions does notresult in the mower “lurching”, as discussed above. In some embodimentsof the invention, the compensated control linkage system 133 comprises afirst control linkage 136, including first end 136 a and second end 136b, wherein the first end 136 a is coupled to control paddle assembly134, and the second end 136 b is coupled to a first end 138 a of a bellcrank 138. In some embodiments, the second end 138 b of the bell crank138 is coupled to the first end 140 a of the second control linkage 140,and the second end 140 b of the second control linkage 140 is coupled tothe bell crank 142 coupled to the conventional hydrostatic transaxlepump valve (now shown).

In some embodiments as described, the compensated control linkage system133 can compensate for movement of the subframe 112. Without thiscompensation, the degree change between the uncompressed and compressedconditions of the suspension system 103 would be significant enough tocause undesirable movement of the mower in some instances during theparked or neutral condition. While a change of angle I of 1.32 degreesis shown in FIG. 9, it is also possible for a compensated controllinkage assembly 133 to be configured to achieve various changes ofangle I, dependent upon the hydrostatic transaxle type and style. Forexample, an angular displacement of less than 1.32 degrees of angle I(e.g., zero degrees or substantially close to zero degrees) could beachieved, or an angular displacement of angle I of greater than 1.32degrees could be achieved for a hydrostatic transaxle capable oftolerating such a displacement without imparting movement on the drivewheels 104. In some embodiments, the compensated control linkageassembly 133 is configured and arranged to reduce and eliminate theamount of angle I change on the control paddle 134 when the suspensionsystem 103 including a suspension component 126 as the arm 126compresses and decompresses, and the shock length decreases andincreases. In some further embodiments (not shown), the amount of anglechange can be further reduced or eliminated with other adjustments tothe linkage positions and lengths. For example, by adjusting the lengthand travel distance of the first control linkage 136, the second controllinkage 140, and by modifying the rotational circumference of the bellcrank 138 or bell crank 142, the amount of change of angle I can beadjusted.

FIG. 10 a illustrates a perspective close-up view of the lower portionof the compensated control linkage assembly 133 and FIG. 10 billustrates a perspective close-up view of the upper portion of thecompensated control linkage assembly 133. As shown, some embodiments ofthe invention include a variety of support components. For example, asshown in FIG. 10 b, bell crank 138 can be pivotably mounted tocompensator arm 310, which is further coupled to compensator link 300.As shown in FIG. 10 a, the compensator arm 310 can be coupled to acompensator lock 320. In some other embodiments, the compensated controllinkage assembly 133 including first control linkage 136, bell crank138, second linkage 140 and bell crank 142 can be coupled to the mainframe 102 and the subframe 112 using alternative couplings.

Some embodiments can feature alternative suspension systems 103. Forexample, referring to FIG. 11, showing a perspective view of thesubframe 112 and hydrostatic transaxle 114, the hydrostatic transaxles114 are mounted to subframe 112 from below. In some other embodiments,as shown in FIG. 12 the hydrostatic transaxles 114 are mounted to asubframe 212 from above, which may account for variations in ZTR mowerdesign, size, etc. Some other embodiments can feature alternativesubframe 112 designs and alternative hydrostatic transaxles 114 designs.In some embodiments, the subframe 112 and hydrostatic transaxle 114 canbe coupled in other ways. One of ordinary skill in the art willunderstand that while the illustrated embodiments are directed to ZTRmowers, many embodiments of the invention are equally useful with othertypes of mowers as well.

As discussed earlier in reference to FIG. 3, illustrating a compressedstate of the suspension system 103, in some embodiments, each of thecomponents mounted on subframe 112 rotate about pivot axis 116 whencompressed. This includes idler pulley(s) 118, backside idler pulleys120 a, 120 b, and driven pulleys 122 a, 122 b on hydrostatic transaxles114. Hence, in some embodiments, idler pulley(s) 118 and backside idlerpulleys 120 a, 120 b travel in the same pulley plane 400 as drivenpulleys 122 a, 122 b upon rotation about pivot axis 116. Because thepulleys 118, 120 a, 120 b travel in the same pulley plane 400, in someembodiments, the change in the belt 132 angle is minimized when thesubframe 112 travels through its suspension arc, and therefore belt 132misalignment is also minimized. As described earlier, if the idlerpulleys 118, 120 a, 120 b were to travel or rotate about a differentplane than driven pulley 122 a, 122 b (i.e. pulley plane 400) onhydrostatic transaxle 114, then significant belt 132 misalignment(caused by a belt 132 angle change) may encourage the belt 132 to “jump”off of the pulley system, thereby rendering the system inoperable.However, as described earlier in FIGS. 2 and 3, in some embodiments, theonly belt 132 angle change between pulleys in the present embodimentwould be between backside idler pulleys 120 a, 120 b and drive pulley110 mounted to the power take-off shaft 109. The risk of belt 132 “jump”due to misalignment is greatly diminished under this configurationbecause there is a significant distance between backside idler pulleys120 a, 120 b and drive pulley 110, thereby minimizing the belt 132 anglechange when subframe 112 travels through its suspension arc (i.e. duringa change of angle I). Furthermore, the significant distance between thedrive pulley 110 and the backside idler pulley 120 b maintains the angleof the endless belt 132 to 3 degrees or less, and prevents belt 132misalignment between these pulleys when subframe 112 travels through itssuspension arc. Moreover, backside idler pulleys 120 a, 120 b have ahigher tolerance for belt 132 angle changes during operation than othertypes of pulleys.

Some embodiments of the invention can be seen in FIG. 13, showing a topsectional view of the hydrostatic transaxle drive system components,including further details of the pulley and belt drive assembly 117.Specifically, FIG. 13 shows the location of the backside idlers 120 a,120 b and their positional relationship with the engine 108, and thedrive pulley 110 (illustrated as endless belt 132 curvature over theengine 108) according to some embodiments of the invention. As shown, insome embodiments, the endless belt 132 can be coupled between the drivepulley 110 coupled to an internal combustion engine 108, backside idlerpulleys 120, idler pulley 118, and driven pulley 122 a, 122 b onhydrostatic transaxle 114. As detailed above, backside idler pulleys 120a, 120 b, idler pulley 118, and driven pulleys 122 a, 122 b onhydrostatic transaxle 114 each travel in the same pulley plane 400 whilethe subframe 112 travels about its suspension arc. Thus, in someembodiments, the only change in angle of endless belt 132 occurs betweendrive pulley 110 coupled to internal combustion engine 108 and backsideidler pulley 120 a, 120 b. However, in some embodiments, because of thesignificant distance between drive pulley 110 and backside idler pulleys120 a, 120 b, made possible by the placement of backside idler pulleys120 a, 120 b near pivot 115 and pivot axis 116 on suspended subframe112, the change in belt 132 angle during suspended operation isminimized. Accordingly, the likelihood of belt slip or “jump” due tobelt 132 angle change is also minimized.

Further views of the various hydrostatic transaxle drive systemcomponents including the pulley and belt drive assembly 117 can be seenin FIGS. 14A and 14B. As shown, in some embodiments, one or morehydraulic drive systems can comprise a drive pulley 110, coupled to apower take-off shaft 109, coupled to an engine 108. In some embodiments,the drive pulley 110 can be coupled to one or more pulley and idlepulleys coupled to one or more hydrostatic axles 114. For example, asshown in FIGS. 14A and 14B, in some embodiments, the drive pulley 110can be coupled to backside idler pulleys 120 a, 120 b, driven pulleys122 a, 122 b, and belt idler pulley 118, all of which can be positioneda significant distance from the drive pulley 110.

In some embodiments, idler pulley(s) 118 and backside idler pulleys 120a and 120 b are attached to the subframe 112 via a conventional spindle(not shown) to allow rotation of the pulleys. In some other embodiments,they can be attached via a plate 124 to front suspension mount 220. Insome embodiments, idler pulley(s) 118 and backside idler pulleys 120 a,120 b receive an endless belt 132 (not shown) that is driven by drivepulley 110 on the power take-off shaft 109 of internal combustion engine108. In some further embodiments, the endless belt 132 is also receivedby driven pulleys 122 a, 122 b coupled to the hydraulic pump (not shown)of hydrostatic transaxle 114. As described earlier, in some embodiments,the only belt 132 angle change between pulleys in the presentembodiments would be between backside idler pulleys 120 a, 120 b, anddrive pulley 110 mounted to the power take-off shaft 109. As previouslydescribed, the significant distance between backside idler pulleys 120a, 120 b and drive pulley 110 minimizes the belt 132 angle change whensubframe 112 travels through its suspension arc.

As described previously, in some embodiments, the ZTR mower 10 includesat least one power source such as an internal combustion engine 108, andin some embodiments, the internal combustion engine 108 can power atake-off shaft 109 coupled to at least one hydrostatic axles 114 via anendless belt 132. In alternative embodiments, the at least one powersource can include a current source and the ZTR mower 10 can be driventhrough the rear drive wheels 104 by at least one electric driveassembly (not shown). For example, in some embodiments, a current sourcecomprising at least one battery (not shown) can be supported by the mainframe 102 and be capable of being electrically coupled to at least oneconventional electric drive assembly (not shown) including at least oneelectric motor (not shown). In some embodiments, the at least onebattery can be electrically coupled to the at least one electric motorusing at least one electrical harness (not shown).

In some embodiments, the at least one power source can include at leastone rechargeable battery. In some embodiments, the at least onerechargeable battery can be at least partially charged from an externalpower supply. For example, in some embodiments, the ZTR mower 10 canincluded a main frame 102 supporting at least one rechargeable batterythat can be at least partially charged from an electrical outlet oranother source of electricity. In some other embodiments, the ZTR mower10 can include an onboard power supply. For example, in someembodiments, the ZTR mower 10 can include rechargeable battery supportedby the main frame 102 that can be at least partially charged from aninternal combustion engine 108. In some embodiments, the engine 108 canbe electrically coupled to at least one onboard current generator or analternator (not shown) powered by the engine 108. In some embodiments,the onboard current generator can be capable of at least partiallyrecharging the at least one battery. In some other embodiments, theonboard current generator can be at least partially able to power the atleast one electric motor independently, or via the at least onerechargeable battery. In some embodiments, the at least one rechargeablebattery resides within the subframe 112, and the engine 108 is residesoutside of the subframe 112, supported on the main frame 102. In someother embodiments, the engine 108 can be electrically coupled to atleast one onboard current generator powered by the engine 108, furthercoupled to at least one rechargeable battery mounted to the subframe. Insome embodiments, the rechargeable battery can be recharged by theengine 108 via the current generator.

Some embodiments of the invention include a subframe 112 pivotallycoupled to a main-frame 102 about a pivot axis of a ride-on equipmentthat includes at least one electric motor supported by the subframe 112.In some embodiments, the at least one electric motor is electricallycoupled to at least one battery positioned external to the subframe 112and supported by the main-frame 102. In some embodiments, the electricmotor is configured and arranged to be powered by the at least onebattery for driving at least one wheel 104 and the pivot axis residessubstantially between the at least one electric motor and the at leastone battery.

In some other embodiments, the ZTR mower 10 can include at least onedrive shaft (not shown) coupled to at least one drive wheel 104. In someembodiments, the main frame 102 includes at least one at least one powersource such as an internal combustion engine 108, and in someembodiments, the engine 108 can be coupled to the drive shaft. Someembodiments of the invention include a subframe 112 pivotally coupled toa main-frame 102 about a pivot axis of a ride-on equipment. In someembodiments, the engine 108, supported by the main frame 102, butunsupported by the subframe 112, is coupled to at least one wheel 104coupled to the subframe 112. In some embodiments, the at least one wheelis driven by the drive shaft coupled to the engine 108 and the pivotaxis resides substantially between the at least one wheel and the engine108.

It will be appreciated by those skilled in the art that while theinvention has been described above in connection with particularembodiments and examples, the invention is not necessarily so limited,and that numerous other embodiments, examples, uses, modifications anddepartures from the embodiments, examples and uses are intended to beencompassed by the claims attached hereto. The entire disclosure of eachpatent and publication cited herein is incorporated by reference, as ifeach such patent or publication were individually incorporated byreference herein. Various features and advantages of the invention areset forth in the following claims.

1. An independent suspension assembly coupled to a main-frame of ride-onequipment, the independent suspension assembly comprising: a subframecomprising a first support having a first end and a second supporthaving a first end; the first support and second support coupled by atleast one substantially horizontal third support; a pivot coupled to thefirst end of the first support and the first end of the second support,the pivot configured and arranged to enable pivotal rotation of thesubframe on the main frame around a pivot axis; at least one motionabsorbing suspension component including a first end coupled to the mainframe and a second end coupled to a second end of at least one of thesupports, the at least one motion absorbing suspension componentconfigured and arranged to be capable of transferring kinetic energy toand from the subframe during pivotal motion of the subframe about themain-frame; and at least one transaxle assembly supported by thesubframe and coupled to at least one external power source, wherein thetransaxle assembly is configured and arranged to be capable of beingdriven by the at least one external power source; the at least oneexternal power source positioned external to the subframe and supportedby the main-frame; and wherein the pivot axis is located substantiallybetween the at least one transaxle assembly and the at least oneexternal power source.
 2. The independent suspension assembly of claim1, wherein the at least one transaxle assembly includes at least onedriven pulley positioned substantially within the subframe and coupledto at least one component that is supported by the subframe, the drivenpulley capable of being coupled to the external power source by leastone driven belt.
 3. The independent suspension assembly of claim 1,wherein the at least one transaxle assembly is configured and arrangedto be capable of being driven by the at least one external power sourceduring pivotal motion of the subframe about the main-frame.
 4. Theindependent suspension assembly of claim 1, wherein the at least oneexternal power source is a current source, and the at least onetransaxle assembly includes at least one electric motor capable of beingpowered by the current source.
 5. The independent suspension assembly ofclaim 4, wherein the current source is a battery.
 6. The independentsuspension assembly of claim 1, wherein the at least one transaxleassembly is a hydrostatic transaxle.
 7. The independent suspensionassembly of claim 3, wherein the at least one external power source iscoupled to the at least one transaxle assembly via at least one driveshaft capable of driving the at least one transaxle assembly.
 8. Theindependent suspension assembly of claim 2, further comprising: a firstbell crank pivotally coupled to a compensator arm and a first controllinkage and a second control linkage; wherein the compensator arm ismounted to the subframe; and a second bell crank including a second axispivotally coupled to the subframe and to the second control linkage andto the first control linkage and the at least one drive component; andwherein the second bell crank is configured and arranged to at leastpartially actuate the at least one drive component when the first bellcrank rotated.
 9. The independent suspension assembly of claim 8,further comprising: at least one control paddle assembly coupled to themain frame and the at least one compensated control linkage via thefirst control linkage; and wherein the at least one control paddle isconfigured and arranged to move the first bell crank.
 10. Theindependent suspension assembly of claim 1, wherein the at least onemotion absorbing suspension component is a shock absorber.
 11. Theindependent suspension assembly of claim 10, wherein the shock absorberis a coil-spring type shock.
 12. The independent suspension assembly ofclaim 11, wherein the subframe and the compensated control linkage areconfigured and arranged wherein a compression of the at least one motionabsorbing suspension component resulting in a decrease of componentlength of two inches decreases the angle between the first axis of thesubframe and the second axis of the second bell crank no greater than1.32 degrees.
 13. The independent suspension assembly of claim 2,further comprising a pulley and belt drive assembly, the pulley and beltdrive assembly including: at least one belt idler pulley positionedsubstantially within the subframe and coupled to at least one componentthat is supported by the subframe; at least one backside idler pulleypositioned substantially within the subframe and coupled to at least onecomponent that is supported by the subframe; wherein the at least onebackside idler pulley is positioned substantially in the same plane asthe at least one driven pulley and the at least one belt idler pulley;and at least one endless belt coupled with the at least one drivenpulley, the at least one belt idler pulley and the at least one backsideidler pulley.
 14. The independent suspension assembly of claim 13,wherein the at least one endless belt is further coupled with at leastone drive pulley positioned substantially outside the subframebackspace, the at least one drive pulley being mounted so that it doesnot pivot around the pivot axis.
 15. The independent suspension assemblyof claim 14 wherein the subframe and the compensated control linkage areconfigured and arranged wherein a compression of the at least onecompressible component causing a decrease of component length of twoinches therein decreases the angle between the first axis of thesubframe and the second axis of the second bell crank not greater than1.32 degrees, and the change of belt angle between the at least onebackside idler pulleys and the drive pulley is not greater than 3degrees.
 16. The independent suspension assembly of claim 14, whereinthe at least one drive pulley is coupled to a power take-off shaft. 17.The independent suspension assembly of claim 16, wherein the at leastone drive pulley is configured and arranged to rotate the at least onebackside idler pulley.
 18. The independent suspension assembly of claim16, wherein the at least one drive pulley is coupled to rotate thedriven pulley.
 19. The independent suspension assembly of claim 16,further comprising an auxiliary drive pulley coupled to the powertake-off shaft.
 20. The independent suspension assembly of claim 19,further comprising a cutter assembly coupled to the auxiliary drivepulley by at least one belt.
 21. The independent suspension assembly ofclaim 16, wherein an engine is coupled to and supported by the mainframe.
 22. The independent suspension assembly of claim 21, wherein amower deck is coupled to and supported by the main frame
 23. Anindependent suspension assembly pivotally coupled to a main-frame ofride-on equipment, the independent suspension assembly comprising: asubframe including a pivot axis and comprising a first support having afirst end and a second support having a first end; the first support andsecond support coupled by at least one substantially horizontal thirdsupport; a pivot coupled to the first end of the first support and thefirst end of the second support, the pivot configured and arranged toenable pivotal rotation of the subframe with respect to the main framearound the pivot axis; at least one motion absorbing suspensioncomponent including a first end coupled to the main frame and a secondend coupled to a second end of at least one of the supports, the atleast one motion absorbing suspension component configured and arrangedto be capable of transferring kinetic energy to and from the subframeduring pivotal motion of the subframe about the main-frame; and at leastone electric motor supported by the subframe and electrically coupled toat least one battery positioned external to the subframe, wherein theelectric motor is configured and arranged to be powered by the at leastone battery for driving at least one drive member; and wherein the pivotaxis is located substantially between the at least one electric motorand the at least one battery.
 24. An independent suspension assemblypivotally coupled to a main-frame of ride-on equipment, the independentsuspension assembly comprising: a first support having a first supportfirst end, wherein a first bushing is coupled to the first support firstend; a second support having a second support first end, wherein asecond bushing is coupled to the second support first end; a thirdsupport having a third support first end affixed to a first supportsecond end and a third support second end coupled to a second supportsecond end; a pivot mounting the first support and the second support toa substantially horizontal chassis support and including a pivot axis,at least one electric motor supported by at least one of the firstsupport, the second support and the third support, the at least oneelectric motor electrically coupled to at least one battery supported bythe mainframe and substantially unsupported by any of the first supportand the second support and the third support, wherein the at least oneelectric motor is configured and arranged to be powered by the at leastone battery for driving at least one drive member; and wherein the pivotaxis is located substantially between the at least one electric motorand the at least one battery.
 25. An independent suspension assemblypivotally coupled to a main-frame of ride-on equipment, the independentsuspension assembly comprising: a first support having a first supportfirst end, wherein a first bushing is coupled to the first support firstend; a second support having a second support first end, wherein asecond bushing is coupled to the second support first end; a thirdsupport having a third support first end coupled to a first supportsecond end and a third support second end coupled to a second supportsecond end; a pivot mounting the first support and the second support toa horizontal chassis support and including a pivot axis, at least onetransaxle assembly supported by at least one of the first support, thesecond support and the third support, the at least one transaxleassembly coupled to at least one driven pulley capable of being coupledto an external power source by least one driven belt; and wherein atleast a portion of the driven belt is located above the pivot axis; andwherein the pivot axis is located substantially between the at least onetransaxle assembly and the at least one external power source.